Fountain pen



Jan. 21, 193a N, G; BURGSTER 2,028,645

FOUNTAIN PEN Filed July 10, 1933 INVE TOR.

Patented Jan. 21, 1936 UNITED STATES PATENT OFFICE I FOUNTAIN PEN v Nathan G. Burgster, Chicago,'lll. Application July 10, 1933, Serial No. 679,636

12 Claims. (Cl. -47) This invention provides an improved type of pump-fill fountain pen of simple construction, few parts and large ink capacity, without packed joints or soft rubber parts.

Among the difiiculties encountered with many types of piston pens is the trapping of ink above the piston, and an important object of this in vention is to provide an arrangement of parts which permits free passage of ink from above the piston to space below the piston.

Another important object is to provide a piston of simple and durable construction.

Referring to the drawing which form: a part of this specification:

Fig. 1 is a vertical section of a pen embodying features of my invention.

Fig. 2 is a cross-section on line 2-2 in Fig. 1.

Fig. 3 is a fragmentary vertical section show ing loose coupling between two sections of piston-rod, and wide passage above upper edge of piston.

Fig. 4 is a partial vertical section showing piston resting in contact with the side of enlargement of inside of barrel, and wide passage between piston and wall of enlargement.

Fig. 5 shows a variation of construction shown in Fig. 3.

Fig. 6 is a partial vertical section showing piston-rod loosely mounted in cap.

Fig. 7 is a partial vertical section showing piston-rod. confined in guide-channels to prevent rotation.

Fig. 8 is a cross-section on line 88 in Fig. 7.

A form of the invention is shown in Fig. l, which is a longitudinal central cross-section, in

which the piston I engages the inner wall of the barrel 2 with a close sliding contact. The piston l consists of a disk of felt, or other flexible material, supported from below by a rigid disk 3, of slightly smaller diameter than piston I, and held down by a small piece 4 which is rigidly attached to piston-rod 5 (ormay be a part thereof). Thus it is evident that on the upstroke of the piston, the air in the barrel below' the piston will be rarefied, causing ink to be drawn into the barrel thru feed and fill channel 6. There is some leakage of air thru a permeable material such as felt, but not. sufiicient to prevent functioning when wet. Such a piston must be thoroly wetted before filling the pen for the first, time, or if piston has been allowed to become dry. On the down-stroke of the piston the ink already drawn in is prevented from running out by gravity (or being forced out'by the piston) by checkvalve I, and as the piston is being returned downward the air or ink will bend the edges of piston upward and pass to the space above the piston. Felt is practically unaffected by the chemical constituents of writing inks, is subject to very slight wear against a smooth barrel, and should last indefinitely in such service.-

, Fig. 2 is a cross-section of the pen at 2-4 in Fig. 1, showing one form of piston-rod. This rod is fiat-instead of round, and slides freely thru aperture I! in end of barrel.

The piston is reciprocated a number of times until the barrel is full. I

. In order that ink above the piston shall feed to the pen I provide an enlarged section of the inside of the barrel from 8 to 9 in Fig. 1, at the part of the barrel where piston rests when the pen is closed and ready for use. This enlarged portion is located at or near the middle of the length of the barrel, because here, in the kind of pen currently used, the barrel is thickest, and consequently a chamber of greater diameter may beobtained at this point than could be obtained near either end of the barrel, without making the walls of the barrel at the chamber so thin as to be impractical on account 02 weakness. Such a chamber is not new, but its location in the middle of the length of the barrel Ibelieve to be new.

If the barrel is thick enough, the space around the piston, as it rests in the chamber, may be made sufiicient to provide interchange of air and ink between the spaces above and below piston, but-I do notwish to be limited to the use of a barrel of anygiven thickness, so I have provided several variations, hereinafter described.

Fig. 3 shows a loose coupling between two sections of thepiston-ro'd, by means of which the piston may rest by gravity against the low side of the barrel when same is in an inclined position, as in writing. Y 7

Inks differ in viscosity, but bubbles form easily in all inks. A film of ink extending from the upper edge of the piston to the wall of the barrel (Figs. 3, 4 and 5) will tend to hold its position against air pressure, and no ink that may be in the barrel above the piston will flowpast the piston into space below unless a corresponding volume of air can pass in the opposite direction at the upper edge of the piston. The; force necessary to break the film is furnished by the weight of the ink' in the barrel above the piston, assisted by the slight jarring incident to the use of the pen in writing. The wider the film the ;more easily it may be broken, and the variations herein described are all aimed at the securing of a substantial space between the top edge of the piston and the barrel.

The presence or absence of the enlargement of the barrel, or its location, are unimportant, provided that there is sufiicient difference in diameter between the part of the barrel in which the piston exerts suction and the part of the barrel immediately below, in which the piston rests-when not in use. It is immaterial whether the chamber is relatively short or long, or whether or not it extends the entire length of the barrel below the effective travel of the piston. The desired relativity may be obtained in one way, for example, by making the part 01' the barrel in which piston exerts suction, of small inside diameter, leaving rather thick walls, and having the remainder of the barrel of much larger inside diameter, with walls of normal thickness. In a barrel so constructed, the chamber 8-9 need not be.used,.or may be used if desired to effect the greatest economy of space, material and ink capacity.

Another variation is shown in Fig. 4, wherein piston-rod 5 is slightly curved in one plane, causing the piston to press against the side of the enlarged portion of barrel. Such a piston-rod is preferably flexible.

The features shown in Figs. 3 and 4 may be combined as shown in Fig. 5, which allows piston to tip even more than it bottom end of top section of piston-rod were centrally disposed in barrel, thus affording a maximum of space for the passage oi! air above the top edge of piston.

When employing a piston-rod rigidly secured in cap H (as in Fig. 1) and using the features shown in Figs. 3, 4 or 5, the piston should be in contact with the low side of the barrel when in writing position, so that air may pass upper edge of piston and thus permit ink above piston to pass to space below. This may be assured by care in assembling. With piston-rod tightly secured in cap H. and said cap tightly screwed onto'barrel, adjust position of nib and feed-bar in point section so that when point section is screwed up tightly, piston will be in contact with low side of barrel when writing. As the threads wear down a readiustmentof, nib and feed-bar in point section maybe easily made.

Fig. 6 shows another variation, wherein piston-rod is loosely mounted in cap ll, permitting it to swing, so that the piston attached to its lower end may move by gravity into contact with low side 01' barrel (within the enlarged portion of the same as shown in Fig. 1 et al.).

Loose mounting oi piston-rod in cap I I, together with a-curved piston-rod as shown in Fig. 4, may be combined with guide-channels in end of barrel, as shown in Fig. 7, so that cap ll rotates independently of piston-rod andlatter does not rotate in barrel, whereby piston attached to piston-rod, when not in use, is pressedagainst side of enlarged portion of barrel. This arrangement makes it easier to insure that piston will rest against low side of barrel when penis in writing position; all that need be done is to as semble the nib and feed-bar in the point section so that the desired relative positions of piston and nib are maintained when point section is screwed home. Fig. 8 is a cross-section at 8-8 in Fig. 7. Piston-rod 5 slides freely thru guidechannels l3. 1

In a pen having a transparent barrel, which embodies no provision against overfllling except visual observations, it is desirable that the transparncy of the barrel be maintained against the tendency toward partial or even total opacity produced by deposit of sediment on the inside 01' the barrel. I have found that the wiping action of the piston removes much of this accumulation and preserves the transparency of the portion of 5 the barrel in which the piston travels. Inasmuch as the most important part of the barrel, so far as observing the rising level of ink is concerned, is the extreme top end, it is highly desirable that it be kept transparent. consequently I provide that the piston may be drawn up to the extreme top end of the inside 01' the barrel, so that the benefit of its wiping action may accrue to the extreme top end of the ink reservoir.

Any other type of piston which will allow passage of air or ink on down-stroke may be used instead of the pistons herein described.

The ball-valve shown at 1 in Fig. 1 is not new.

It rolls off its seat when pen is tilted to writing position. To'fill the pen, cap H is unscrewed, point section immersed in a supply of ink, the pen held in an approximately vertical position, and the piston reciprocated by means of the cap II as an operating handle.

On up-stroke the air below tha piston is rarefied and ink is drawn into reservoir thru duct 6, and thru check-valve I which opens by reason of pressure of fluid below it and offers no resistance to upward passage of fluid. At the same time the air above the piston escapes thru opening I! in the top end of the barrel. On down-stroke the ink already drawn into the reservoir is retained therein by check-valve 'l which seats by gravity as soon as ink ceases to flow upward thru it, and piston travels downward with slight resistance against the air below it because of its valve action, the edges flexing backward to allow the air to pass by it. When further upstrokes have drawn in a considerable quantity of 40 ink, the piston passes down thru the ink by the same valve action which takes place when there is only air below it, both fluids acting alike in this respect. When level of ink rises to top of barrel the cap I I is screwed onto barrel and pen is ready. for use. It barrel is made of transparent material the rising level of ink may be seen and pumpsuch changes as fall within the scope of the claims.

I claim,

1. In a fountain-pen: a barrel, an opening in the top end of barrel, a cap adapted to close said opening, a piston-rod loosely mounted in said cap and slidable thru said opening, lower end of said piston-rod, when in itslowest posi- 00 tion, being free to move laterally.

2 In. a fountain-pen: a barrel, an opening in the top end of barrel, 9. cap adapted to close said opening, a piston-rod swivelly and loosely mounted in saidcap and slidable thru said open- 05 mg, two channels positioned opposite to each other in said opening, thru which channels piston-rod is slidable, said channels preventing piston-rod from rotating in barrel, said piston-rod being loosely confined by said channels whereby 7o sidewise motion 01' said piston-rod is permitted in a plane intersecting said channels.

3. In a fountain-pen: a barrel, an opening in the top end 01 barrel, a cap adaptedto close said opening, a piston-rod swivelly mounted in u said cap, means for preventing rotation of rod in barrel, a piston carried by said pis on-rod, an enlargement of inside of barrel below that-part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement, and means for causing piston-rod and piston attached thereto to exert lateral-pressure against one side of barrel, whereby, when piston is within said eniargement said pressure causes a portion of the periphery of said piston to rest in contact with side of said enlargement,

leaving space between piston and enlargement except at place of contact.

4. In a fountain-pen: a barrel, an opening in the top end of barrel, a'cap adapted to close said opening, a flexible and elastic plston -rod of oblong cross-section swivelly mounted in said cap and slidable thru said opening, said piston-rod being slightly curved longitudinally in the plane of its greatest width, two channels parallel to axis of barrel in opposite sides of said opening, the

edges of said piston-rod sliding in said channels, a piston rigidly attached to said piston-rod, an enlargement of inside of barrel below that part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement, the retention of said piston-rod within said channels, when piston is within said enlargement, causing lower end of rod to lie closer to side of barrel facing concavity of curve in said rod than to opposite side, whereby a part of periphery of piston attached to said rod is forced to follow the contour of said enlargement and to be in contact with side of said enlargement, such side being meme facing the concavity of curve in said rod, leaving space between piston and enlargement except at place of contact.

5. In a fountain-pen: a barrel, an opening in the top end of barrel, a cap adapted to close said opening, a piston-rod swivelly mounted in said cap and slidable thru said opening, means for preventing rotation of piston-rod in barrel, a piston carried by said piston-rod, and an enlargement of inside of barrel below that part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement.

6. In a fountain-pen: a barrel, an opening in the top end of barrel, a piston-rod slidable thru said opening, channels in said opening, said rod being operated thru and conflned by said channels, whereby it is prevented from rotating in barrel, a piston carried by said piston-rod and an enlargement of inside of barrel below that part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement.

7. In afountain-pen: a barrel, an opening in the top end of barrel, a cap adapted toclose said opening, a piston-rod of oblong cross-section swivelly mounted in said cap, channels in opposite sides of said opening, the edges of said rod sliding in said channels, a piston carried by said piston-rod, and an enlargement of inside of barrel below that part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement.

8. In a fountain-pen: a barrel, an opening in the top end of barrel, a cap adapted to close said opening, a piston-rod swivelly mounted in said cap and slidable thru said opening, channels parallel to axis of barrel in opening at top end of barrel, thru which channels piston-rod is slidable, said channels preventing piston-rod from rotating in barrel, a piston carried by said vpiston-rod, an enlargement of inside of barrel below that part of barrel in which piston performs its function, said piston resting, when not in use, within said enlargement, means for automatically causing said piston to rest against low side of barrel,

the bore having an enlargement adjacent the part where the piston is located in normal position, and means for causing movement of the piston to one side of the enlargement.

10. In a fountain-pen: the combination of a barrel, a piston movable within the barrel, an enlargement of the inside of the barrel, said piston resting, while not in use, within said enlargement, and means for causing movement of said piston to one side of said enlargement.

11. In a fountain-pen which is filled by the action of a piston: means to facilitate the free passage of fluid between the space above the piston and the space below the piston while the piston is not in use, comprising a barrel, a piston movable within the barrel, an enlargement of the inside of the barrel, said piston resting while not in use, within said enlargement, and means for causing movement of said piston to one side of said enlargement.

12. In a fountain-pen which is filled by the action of a pistonzmeans to facilitate the free passage of fluid between the space above the piston and the space below the piston while the piston is not in use, comprising a barrel, a piston movable within the barrel, an enlargement of the inside of the barrel, said piston resting, while notin use, within said enlargement, means for causing movement of said piston to one side of said enlargement, and means for holding said piston in contact with one side of said enlargement.

NATHAN G. BURGSTER. 

